sendmail linux command

sendmail

sendmail [flags] [address]

System administration command. sendmail is a mail transfer agent (MTA) or, more simply, a mail router. It accepts mail from a user's mail program, interprets the mail address, rewrites the address into the proper form for the delivery program, and routes the mail to the correct delivery program.

Command-line flags

-bx

Set operation mode to x. Operation modes are:

a

Run in ARPAnet mode.

d

Run as a daemon.

i

Initialize the alias database.

m

Deliver mail (default).

p

Print the mail queue.

s

Speak SMTP on input side.

t

Run in test mode.

v

Verify addresses; do not collect or deliver.

-C file

Use configuration file file.

-d level

Set debugging level.

-F name

Set full name of user to name.

-f name

Sender's name is name.

-h cnt

Set hop count (number of times message has been processed by sendmail) to cnt.

-n

Do not alias or forward.

-o x value

Set option x to value value. Options are described below.

-p protocol

Receive messages via the protocol protocol.

-q [time]

Process queued messages immediately, or at intervals indicated by time (for example, -q30m for every half hour).

-r name

Obsolete form of -f.

-t

Read head for To:, Cc:, and Bcc: lines, and send to everyone on those lists.

-v

Verbose.

-X file

Log all traffic to file. Not to be used for normal logging.

Configuration options

The following options can be set with the -o flag on the command line or the O line in the configuration file:

Format all incoming messages in 7 bits.

amin

If the D option is set, wait min minutes for the aliases file to be rebuilt before returning an alias database out-of-date warning.

Afile

Use alternate alias file.

bminblocks[/maxsize]

Require at least minblocks to be free, and optionally set the maximum message size to maxsize. If maxsize is omitted, the slash is optional.

Bchar

Set unquoted space replacement character.

c

On mailers that are considered 'expensive' to connect to, don't initiate immediate connection.

Cnum

Checkpoint the queue when mailing to multiple recipients. sendmail will rewrite the list of recipients after each group of num recipients has been processed.

dx

Set the delivery mode to x. Delivery modes are d for deferred delivery, i for interactive (synchronous) delivery, b for background (asynchronous) delivery, and q for queue only -- i.e., deliver the next time the queue is run.

D

Try to automatically rebuild the alias database if necessary.

ex

Set error processing to mode x. Valid modes are m to mail back the error message, w to write back the error message, p to print the errors on the terminal (default), q to throw away error messages, and e to do special processing for the BerkNet.

Etext

Set error message header. text is either text to add to an error message or the name of a file. A filename must include its full path and begin with a /.

f

Save Unix-style From lines at the front of messages.

Fmode

Set default file permissions for temporary files. If this option is missing, default permissions are 0644.

G

Compare local mail names to the GECOS section in the password file.

g n

Default group ID to use when calling mailers.

Hfile

SMTP help file.

h num

Allow a maximum of num hops per message.

i

Do not take dots on a line by themselves as a message terminator.

I arg

Use DNS lookups and tune them. Queue messages on connection refused. The arg arguments are identical to resolver flags without the RES_ prefix. Each flag can be preceded by a plus or minus to enable or disable the corresponding name server option. There must be a whitespace between the I and the first flag.

j

Use MIME format for error messages.

Jpath

Set an alternative .forward search path.

knum

Specify size of the connection cache.

Ktime

Time out connections after time.

l

Do not ignore Errors-To header.

Ln

Specify log level.

m

Send to me (the sender) also if I am in an alias expansion.

MXvalue

Define a macro's value in command line. Assign value to macro X.

n

When running newaliases, validate the right side of aliases.

o

If set, this message may have old-style headers. If not set, this message is guaranteed to have new-style headers (i.e., commas instead of spaces between addresses).

pwhat,what,

Tune how private you want the SMTP daemon. The what arguments should be separated from one another by commas. The what arguments may be any of the following:

public

Make SMTP fully public (default).

needmailhelo

Require site to send HELO or ELHO before sending mail.

needexpnhelo

Require site to send HELO or ELHO before answering an address expansion request.

needvrfyhelo

Like preceding argument but for verification requests.

noexpn

Deny all expansion requests.

novrfy

Deny all verification requests.

authwarnings

Insert special headers in mail messages advising recipients that the message may not be authentic.

goaway

Set all of the previous arguments (except public).

restrictmailq

Allow only users of the same group as the owner of the queue directory to examine the mail queue.

restrictqrun

Limit queue processing to root and the owner of the queue directory.

Puser

Send copies of all failed mail to user (usually postmaster).

qfact

Multiplier (factor) for high-load queuing.

Qqueuedir

Select the directory in which to queue messages.

R

Don't prune route addresses.

Sfile

Save statistics in the named file.

s

Always instantiate the queue file, even under circumstances in which it is not strictly necessary.

Ttime

Set the timeout on undelivered messages in the queue to the specified time.

tstz, dtz

Set name of the time zone.

Udatabase

Consult the user database database for forwarding information.

uN

Set default user ID for mailers.

v

Run in verbose mode.

Vhost

Fall-back MX host. host should be the fully qualified domain name of the fallback host.

w

Use a record for an ambiguous MX.

xload

Queues messages when load level is higher than load.

Xload

Refuse SMTP connections when load is higher than load.

yfactor

Penalize large recipient lists by factor.

Y

Deliver each job that is run from the queue in a separate process. This helps limit the size of running processes on systems with very low amounts of memory.

zfactor

Multiplier for priority increments. This determines how much weight to give to a message's precedence header. sendmail's default is 1800.

Zinc

Increment priority of items remaining in queue by inc after each job is processed. sendmail uses 90,000 by default.

sendmail support files

/usr/lib/sendmail

Binary of sendmail.

/usr/bin/newaliases

Link to /usr/lib/sendmail; causes the alias database to be rebuilt.

/usr/bin/mailq

Prints a listing of the mail queue.

/etc/sendmail.cf

Configuration file, in text form.

/etc/sendmail.hf

SMTP help file.

/usr/lib/sendmail.st

Statistics file. Doesn't need to be present.

/etc/aliases

Alias file, in text form.

/etc/aliases.

Alias file in dbm format.

/var/spool/mqueue

Directory in which the mail queue and temporary files reside.

/var/spool/mqueue/qf

Control (queue) files for messages.

/var/spool/mqueue/df

Data files.

/var/spool/mqueue/lf

Lockfiles.

/var/spool/mqueue/tf

Temporary versions of af files, used during queue-file rebuild.

/var/spool/mqueue/nf

Used when creating a unique ID.

/var/spool/mqueue/xf

Transcript of current session.